fasdump : program to dump contents of fas files

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Tarkin

Joined: 27 Aug 2010
Posts: 22

Tarkin 04 Sep 2010, 06:43

...the file? I can't seem to find it... Embarassed

TIA,
Tarkin

04 Sep 2010, 06:43

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20761
Location: In your JS exploiting you and your system

revolution 04 Sep 2010, 06:53

Make sure you are logged in and then see the first post in this thread.

04 Sep 2010, 06:53

DJ Mauretto

Joined: 14 Mar 2007
Posts: 464
Location: Rome,Italy

DJ Mauretto 04 Sep 2010, 07:31

Hello, while testing your program I got an error
'File is corrupt, signature is invalid'
in your source code you define hdr.signature 1B736166 but
fas use 1A736166, i changed in 1A736166 and now it's OK..

Code:

  if (hdr.signature != 0x1B736166)  {
            fprintf(stderr, "File is corrupt, signature is invalid\n");
              goto out_error;
     }

Fasm signature is

Code:

                                flat assembler
                       Symbolic information file format


   Table 1  Header
  /-- -----------------------------------------------------------------------\
  | Offset | Size    | Description                                         |
  |========|=========|======================================================|
  |   +0   |  dword  | Signature 1A736166h (little-endian).               |
  |--------|---------|------------------------------------------------------|

_________________
Nil Volentibus Arduum Razz

04 Sep 2010, 07:31

Tarkin

Joined: 27 Aug 2010
Posts: 22

Tarkin 04 Sep 2010, 07:38

Doh! I have to remember to login...

Have a suggestion:

Code:

#define FASMSIGNATURE 0xDEADBEEF /* Change 0xDEADBEEF to the current fasm signature */
...
/*if (hdr.signature != 0x1B736166)  {*/
  if (hdr.signature != FASMSIGNATURE)  {

For fasm 1.69.18, the signature is 0x1A736166

Thanks for fasdump! I will try and work on a shell script which will filter fasdump's output and
prints out fixed-up addresses ( for Linux ELF 32 ).

TTFN,
Tarkin

04 Sep 2010, 07:38

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8466
Location: Kraków, Poland

Tomasz Grysztar 04 Sep 2010, 08:21

Tarkin wrote:

For fasm 1.69.18, the signature is 0x1A736166

Note: http://board.flatassembler.net/topic.php?p=92185#92185
It was this way for fasm 1.68 already.

04 Sep 2010, 08:21

Tarkin

Joined: 27 Aug 2010
Posts: 22

Tarkin 04 Sep 2010, 08:40

Ah, yes, missed that post. But I was intending it as fix for fasdump, as DJ Mauretto pointed out.

Also, here is the awk one-liner I hinted at earlier:

Code:

fasdump -s prog.fas | awk '/(\.text)|(\.rodata)|(\.bss)/ { OFFSET=0x08048074; ADDR = strtonum($4) + OFFSET ; printf("%s : 0x%08X\n",$1,ADDR)  } '

Thanks all and HTH,
Tarkin

04 Sep 2010, 08:40

mariosk8s

Joined: 29 Oct 2015
Posts: 1
Location: Hüfingen, Germany

mariosk8s 29 Oct 2015, 09:54

I experienced segfaults on linux due to 2s compliment issues when casting (uint32_t)(*token_ptr).
Something like 89 00 00 00 turned into 89 ff ff ff resulting in rather long lengths.
The attached patch makes these char types unsigned (uint8_t).
I also adjusted the hdr.signature to 1B.

I added the .txt extension because of "The Extension patch is not allowed" error when posting.

Description:	patch to make char uint8_t	Download
Filename:	fasdump.patch.txt
Filesize:	3.78 KB
Downloaded:	2258 Time(s)

_________________
Regards

Mario

29 Oct 2015, 09:54

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